1. Field of the Invention
The present invention relates generally to methods and devices for the selective occlusion of body lumens. More particularly, the present invention relates to the methods and devices for drawing opposed portions of the body lumen wall together and subsequently fusing regions of said opposed portions which are in contact with each other together.
The selective occlusion of blood vessels in a patient is a part of many modern therapeutic treatments, including the control of internal bleeding, the occlusion of blood supply to tumors, the isolation of diseased body organs prior to removal, the relief of blood pressure in a region of aneurism, and the like. While such procedures rely generally on the blockage of arteries, the selective occlusion of veins is also useful in procedures such as veiniotomy.
The selective occlusion of blood vessels can be achieved by a variety of specific techniques. Such techniques fall generally into two categories. First, chemical occlusion of blood vessels is typically accomplished by introduction of a non-physiologic solution into the vessel lumen. The solution is selected to destroy the vessel lining and injure the underlying tissue, causing edema, fibrin deposition, and eventually fibrosis of the lumen. In addition to the use of such chemical agents, e.g., ethanol, tetradecyl sulfate, and hypertonic saline, heat can also be applied to induce fibrosis of the lumen.
The second general approach for vessel occlusion is mechanical. For example, in open surgical and endoscopic procedures, the body vessel can be externally clamped and radiofrequency energy applied. While the external procedures can be very effective, it requires external access to the lumen and is unsuitable for endoluminal techniques.
Mechanical endoluminal techniques for selective vessel occlusion are also in use. Such techniques include the use of detachable balloons, embolic coils, and the like to physically block the vessel lumen. Detachable balloons, however, are difficult to deliver and usually not suitable for permanent implantation. Embolic coils are difficult to position, difficult to size for a particular site within a vessel lumen, frequently migrate from the point of initial implantation, and sometimes fail to initiate thrombosis or fibrosis in order to permanently occlude the lumen.
The use of chemical occlusion techniques is also problematic. Chemical occlusion is not readily employed in blood vessels having a high flow rate since the chemical agents are quickly diluted. Moreover, the chemical agents used can cause injury if leakage occurs away from the desired treatment site. Even when the chemical agent is properly released, some individuals can experience systemic toxicity.
Of particular interest to the present invention, the use of monopolar and bipolar radiofrequency devices has been proposed for the endoluminal occlusion of body vessels. For example, U.S. Pat. No. 5,403,311, describes occlusion of a body lumen using electrosurgical electrodes which are transcutaneously positioned within the lumen. Catheters for radiofrequency injury and occlusion of the cystic duct are described in Becker et al. (1989) RADIOLOGY 170:561-562 and (1988) RADIOLOGY 167:63-68. Methods and catheters for electrosurgical endovascular occlusion are described in Brunelle et al. (1980) RADIOLOGY 137:239-240; Cragg et al. (1982) RADIOLOGY 144:303-308; and Brunelle et al. (1983) RADIOLOGY 148:413-415. Such techniques, however, have not generally been useful in large blood vessels.
For these reasons, it would be desirable to provide improved methods and devices for the selective occlusion of body lumens, and particularly of blood vessels, for use in the procedures described above. Such methods and devices should permit the endoluminal occlusion and sealing of body lumens, being effective with large body lumens as well as being suitable for accessing and closure of small body lumens. The methods and devices should provide for relatively immediate occlusion of the vessel, thus permitting occlusion to be radiologically verified at the end of the procedure. The occlusions thus achieved should be permanent and not be dependent on the implantation of coils, balloons, embolization particles, or other devices. Preferably, however, it will be possible to test the occlusion, e.g. observe the result of occlusion of blood flow in a vessel, prior to permanent occlusion of the lumen. Additionally, it would desirable if such methods and devices permitted the formation of multiple occlusions of the same vessel, or single or multiple occlusion of different vessels, during a single procedure, preferably during a single endoluminal introduction of the device.
2. Description of the Background Art
Methods and devices for implanting vasoocclusive elements, such as coils, in blood vessels and other lumen are described in U.S. Pat. Nos. 5,312,415; 5,261,916; 5,250,071; 5,234,437; 5,226,911; 5,217,484; 5,122,136; 5,108,407; 4,994,069; and 3,868,956; and published PCT applications WO 94/11051; WO 94/10936; WO 94/09705; WO 94/06503; and WO 93/06884. Some of the devices described in the above listed patents and published applications suggest passing electrical current through the element to enhance blood clotting.
Electrosurgical probes for electrosurgical, electrocautery, and other procedures are described in U.S. Pat. Nos. 5,405,322; 5,385,544; 5,366,490; 5,364,393; 5,281,216; 4,685,459; 4,655,216; 4,582,057; 4,492,231; 4,209,018; 4,041,952; 4,011,872; 4,005,714; 3,100,489; 2,022,065; 1,995,526; 1,943,543; 1,908,583; and 1,814,791; and published Japanese application 2-121675; published German applications DE 4139029; DT 2646228; and DT 2540968; and published PCT applications WO 95/02366 and WO 93/01758. In particular, U.S. Pat. No. 5,405,322 discloses a dual balloon catheter having a radiofrequency current source with means for evacuating blood from between the balloons, and U.S. Pat. No. 4,011,872 discloses bipolar graspers which can grasp and excise tissue.
See also the patent and publications described in the Field of the Invention above.